Pro Tools 9 External Sound Cards

[eschybach]

I have a few questions that have remained unanswered to me about Pro Tools 9.

1. I've been told PT 9 allows the usage of 3rd party hardware that use core audio or are compatible with core audio. Forgive my ignorance, but how do I know what hardware uses core audio? I have a firewire mixer that talks with my MacBook, does that make it compatible with PT 9?

2. I intend to do recording, editing, and mixing of not only music but film audio. I would LOVE to do it in 5.1, but having a MBP, I do not have the necessary outputs for this. I was thinking about purchasing a USB 5.1 adapter, and they all use external sound cards. Can PT still run using say, the said mixer above (it's a Phonic Helix 12 MKII) and the 5.1 usb adapter, recording, monitoring, mixing, and the whole shebang?

Any help would be wonderful, as I'm trying to decide if it's worth the crossgrade from LE.